Robert c



UNITED STATES PATENT OFFICE.

ROBERT C. sonuPPnAusor BROOKLYN, ASSIGNOR To HUDSON MAXIM,

on NEW YORK, N. Y;

BROCESS OF NITRATING GEL dLOSEI.

srncrrrcn'rron forming part of Letters Application filed November 10,

.To all whom; it may obi warn.-

. Be it known that 1, ROBERT America, residing at the'city otv-Brooklyn,

Kings county, and State of New York, have Manufacturing Guntion.

to I

u-i'factu're of gun I I to the nitration step. of, the process insuch cotton and more particularly inanufactura It is well recogniz'ed'in the process of -ni- .based'soiue:

trating. cellulose thatsu'ccess. is

' what on the uniformity of composition, which when practiced in the usual wayis hard to attain. As the acids bath is weakenedaf- J treatment of the cellue d of the original-strong mixture,'a bath may be ter each' successive lose, difierent niethods have bee'n propose by whichto restore the acids loath to the proper strength. It is also well recognized that it is absolutely essential in order to obtain a uniform produccthat thepvop'ortion's 1 relative changes of acids mixture employed.-

' Ifwe suppose that the mixture consists of three parts of sulfuric acid and one part of the "of'ninety-eightper" after the nitration, on

of the composition'ot theacids shall be at all times uniform. It is obvious be obtained of the high-est gradeof nitration by using the acids bath'over again upong simfor the reason that in the. conversion of to nitro-cellulose, a certain quantity of water is formed. Hence the acids mixture grows richer in sulfuric acid and water and poorer in nitric acid; these being the smaller the larger centrated mixture, I

cellulose in the proportion that one hundred pounds of acids to each pound of cellulose are used, aiIiId t e strongest I stronges't nitric acid, cent. strength, then, I I the assumption that no water has been introsay duced into the acids mixture other-than that that no nitric acid has formed in the reaction, evaporated, and that all the cellulose has been converted into true gun cotton, the percent- C. Sondra. HAUS, a citizen of the United States o f .This invention relates-generally to the man-- that no uniform product can ly replenishing such bath with a fr'esh'com I Patent No. 526,752, dated October 2, 1 894.

1893- Serial No.490,520 ill!) specimens.)

ageof composition of the remaining acids bathwould be:" Z5.-63 sulfuric acid of ninety-- 5o eight per centtstre'ngth, twenty-four nitric acid of ninety-eight perg' cent. strength, and

.37-water. I Y

If the nitro-cellulose is withdrawn from the tity of the original mixture, threeparts sol-5 furic acid and one part nitric acid, the acids solution must necessarily grow'less 'and less fitflto produce gun-cotton, until at last a point is reached when an efitirely fresh acids -bath; the weakened bathin' some instances being used in the prep aration iof collodion'cotto'n and in others is subjected to distillation.

By rejecting a larger quantity of spent acid 65 than that unavoidably lost in the "washing process and replacing it by an equal amount produced yielding ahi'gh' grade gun-cotton; I of "the lower pyroxylin'es and. be variable in composition.- Besides, alarge stock of-vveak- 'ened acids accumulates that must be dis.-

osedof in some way.- I

. The,;pres'ent.i-nvention-isdesigniad to overcom'ethese diff culties and to provide a simple -and, economical method of .,replenishing or bringing the weakened acids bath. to its proper strength and proportions; and-it eo n sists essentiallyin adding nitric acid and sill- 8c 'furicanhydrid to the weakehed acids bath.-

-'In practicing the improved method, after withdrawingthe nitro-cell lose from the acids "bath, the adhering acids are removed either i by means of a centrifugal machine, a press, or .by a suction, filter, and the acids thusrecovered are returnedto-the remainder of the bath. I The bath is "then analyzed and the percentage, of sulfuric and nitric acids of ninety eightpercen'tg'strengthis ascertained. 9o The'surplus of water in this bath is then corn-v bined with sufiicientsulturic anhydrid, c, e.',

cent. strength sulfuric acid, and enough alsoadded to re-establish the pie-existing probath and the bath'be replenished with a quana 5 5 I it is essential to start with 6o but 's'ucli'product will valways contain ;more'7o four times its weight to form ninety-eight per ninety-eight per cent. strength nitricacid is:

store the weakened acids bath 1.42 pounds sulfuric anhydrid, and 1.83 pounds nitric acid of ninety-eight per cent. strength changing the one hundred pounds-0E waste acids-into one hundred and three and thirty-one one hundredths pounds of acids of the original strength'and proportion's.-

It maybe stated that if this gain in weight of 3.31 pounds should not be sufficient to restore the unavoidable loss of acids through the washing process, a solution of sulfuric anhydrid in oil of vitriol may be employed to build up the strength of the waste acids;

and a correspondingly large amount of nitric :0 acid should also be added in such mum.

Whatis claimed is v 1 In the art of nitrating cellulose, theherein described method of restoring the weakened acids bath, which consists in adding thereto 2 5 sulfuric anhydrid and nitric acid.

2. In the art of nitrating cellulose theherein described methodof restoring the weakened acids bath, which consists in adding thereto a solution of suliuric anhydrid and oil of vit- 3o riol and nitric acid. .1

In witness whereof I have hereunto set my hand in the presence of two witnesses.

ROBERT o. SOHUPPHAUS.

Witnesses: GEO. H. GRAHAM;

E. L. Tom). 

